Thomas Aquinas - Summa Theologica, Part III (Tertia Pars)

Reply Obj. 1: As accidental difference makes a thing "other" ( alterum ), so essential difference makes "another thing" ( aliud ). Now it is plain that the "otherness" which springs from accidental difference may pertain to the same hypostasis or suppositum in created things, since the same thing numerically can underlie different accidents. But it does not happen in created things that the same numerically can subsist in divers essences or natures. Hence just as when we speak of "otherness" in regard to creatures we do not signify diversity of suppositum, but only diversity of accidental forms, so likewise when Christ is said to be one thing or another thing, we do not imply diversity of suppositum or hypostasis, but diversity of nature. Hence Gregory Nazianzen says in a letter to Chelidonius (Ep. ci): "In the Saviour we may find one thing and another, yet He is not one person and another. And I say 'one thing and another'; whereas, on the contrary, in the Trinity we say one Person and another (so as not to confuse the subsistences), but not one thing and another."

Reply Obj. 2: Hypostasis signifies a particular substance, not in every way, but as it is in its complement. Yet as it is in union with something more complete, it is not said to be a hypostasis, as a hand or a foot. So likewise the human nature in Christ, although it is a particular substance, nevertheless cannot be called a hypostasis or suppositum, seeing that it is in union with a completed thing, viz. the whole Christ, as He is God and man. But the complete being with which it concurs is said to be a hypostasis or suppositum.

Reply Obj. 3: In created things a singular thing is placed in a genus or species, not on account of what belongs to its individuation, but on account of its nature, which springs from its form, and in composite things individuation is taken more from matter. Hence we say that Christ is in the human species by reason of the nature assumed, and not by reason of the hypostasis. _______________________

FOURTH ARTICLE [III, Q. 2, Art. 4]

Whether After the Incarnation the Person or Hypostasis of Christ Is

Composite?

Objection 1: It would seem that the Person of Christ is not composite. For the Person of Christ is naught else than the Person or hypostasis of the Word, as appears from what has been said (A. 2). But in the Word, Person and Nature do not differ, as appears from First Part (Q. 39, A. 1). Therefore since the Nature of the Word is simple, as was shown above (I, Q. 3, A. 7), it is impossible that the Person of Christ be composite.

Obj. 2: Further, all composition requires parts. But the Divine Nature is incompatible with the notion of a part, for every part implicates the notion of imperfection. Therefore it is impossible that the Person of Christ be composed of two natures.

Obj. 3: Further, what is composed of others would seem to be homogeneous with them, as from bodies only a body can be composed. Therefore if there is anything in Christ composed of the two natures, it follows that this will not be a person but a nature; and hence the union in Christ will take place in the nature, which is contrary to A. 2.

On the contrary, Damascene says (De Fide Orth. iii, 3, 4, 5), "In the Lord Jesus Christ we acknowledge two natures, but one hypostasis composed from both."

I answer that, The Person or hypostasis of Christ may be viewed in two ways. First as it is in itself, and thus it is altogether simple, even as the Nature of the Word. Secondly, in the aspect of person or hypostasis to which it belongs to subsist in a nature; and thus the Person of Christ subsists in two natures. Hence though there is one subsisting being in Him, yet there are different aspects of subsistence, and hence He is said to be a composite person, insomuch as one being subsists in two.

And thereby the solution to the first is clear.

Reply Obj. 2: This composition of a person from natures is not so called on account of parts, but by reason of number, even as that in which two things concur may be said to be composed of them.

Reply Obj. 3: It is not verified in every composition, that the thing composed is homogeneous with its component parts, but only in the parts of a continuous thing; for the continuous is composed solely of continuous [parts]. But an animal is composed of soul and body, and neither of these is an animal. _______________________

FIFTH ARTICLE [III, Q. 2, Art. 5]

Whether in Christ There Is Any Union of Soul and Body?

Objection 1: It would seem that in Christ there was no union of soul and body. For from the union of soul and body in us a person or a human hypostasis is caused. Hence if the soul and body were united in Christ, it follows that a hypostasis resulted from their union. But this was not the hypostasis of God the Word, for It is eternal. Therefore in Christ there would be a person or hypostasis besides the hypostasis of the Word, which is contrary to AA. 2, 3.

Obj. 2: Further, from the union of soul and body results the nature of the human species. But Damascene says (De Fide Orth. iii, 3), that "we must not conceive a common species in the Lord Jesus Christ." Therefore there was no union of soul and body in Him.

Obj. 3: Further, the soul is united to the body for the sole purpose

of quickening it. But the body of Christ could be quickened by the

Word of God Himself, seeing He is the fount and principle of life.

Therefore in Christ there was no union of soul and body.

On the contrary, The body is not said to be animated save from its union with the soul. Now the body of Christ is said to be animated, as the Church chants: "Taking an animate body, He deigned to be born of a Virgin" [*Feast of the Circumcision, Ant. ii, Lauds]. Therefore in Christ there was a union of soul and body.

I answer that, Christ is called a man univocally with other men, as being of the same species, according to the Apostle (Phil. 2:7), "being made in the likeness of a man." Now it belongs essentially to the human species that the soul be united to the body, for the form does not constitute the species, except inasmuch as it becomes the act of matter, and this is the terminus of generation through which nature intends the species. Hence it must be said that in Christ the soul was united to the body; and the contrary is heretical, since it destroys the truth of Christ's humanity.

Reply Obj. 1: This would seem to be the reason which was of weight with such as denied the union of the soul and body in Christ, viz. lest they should thereby be forced to admit a second person or hypostasis in Christ, since they saw that the union of soul and body in mere men resulted in a person. But this happens in mere men because the soul and body are so united in them as to exist by themselves. But in Christ they are united together, so as to be united to something higher, which subsists in the nature composed of them. And hence from the union of the soul and body in Christ a new hypostasis or person does not result, but what is composed of them is united to the already existing hypostasis or Person. Nor does it therefore follow that the union of the soul and body in Christ is of less effect than in us, for its union with something nobler does not lessen but increases its virtue and worth; just as the sensitive soul in animals constitutes the species, as being considered the ultimate form, yet it does not do so in man, although it is of greater effect and dignity, and this because of its union with a further and nobler perfection, viz. the rational soul, as has been said above (A. 2, ad 2).

Reply Obj. 2: This saying of Damascene may be taken in two ways: First, as referring to human nature, which, as it is in one individual alone, has not the nature of a common species, but only inasmuch as either it is abstracted from every individual, and considered in itself by the mind, or according as it is in all individuals. Now the Son of God did not assume human nature as it exists in the pure thought of the intellect, since in this way He would not have assumed human nature in reality, unless it be said that human nature is a separate idea, just as the Platonists conceived of man without matter. But in this way the Son of God would not have assumed flesh, contrary to what is written (Luke 24:39), "A spirit hath not flesh and bones as you see Me to have." Neither can it be said that the Son of God assumed human nature as it is in all the individuals of the same species, otherwise He would have assumed all men. Therefore it remains, as Damascene says further on (De Fide Orth. iii, 11) that He assumed human nature in atomo, i.e. in an individual; not, indeed, in another individual which is a suppositum or a person of that nature, but in the Person of the Son of God.